Use Espressif official Flash Download Tool to download AT firmware bin files into Flash according to the "readme" which is in the attachment.

Notice:1. Firmware upgrade through Wi-Fi (AT+CIUPDATE) is not supported in non-boot mode.2. 4Mbit Flash is not supported in both non-boot mode and with-boot mode.

Firmware upgrade over-the-air process is changed a bit. We will upgrade the latest AT firmware to Espressif Cloud server only after it has been tested and the overall performance is guaranteed. Users may not be able to use AT+CIUPDATE in ESP8266_NONOS_SDK_V1.5.0 and other more advanced versions.

Important LinksHere are the links for this AT release (version ESP82566_AT_v1.1 based on ESP8266_NONOS_SDK_V1.5.4):

Documentation

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Espressif Systems is a fabless semiconductor company providing cutting-edge low power WiFi SoCs and wireless solutions for wireless communications and Internet of Things applications. We are the manufacturer of ESP8266EX.